Mapping out spin and particle conductances in a quantum point contact.

We study particle and spin transport in a single-mode quantum point contact, using a charge neutral, quantum degenerate Fermi gas with tunable, attractive interactions. This yields the spin and particle conductance of the point contact as a function of chemical potential or confinement. The measurements cover a regime from weak attraction, where quantized conductance is observed, to the resonantly interacting superfluid. Spin conductance exhibits a broad maximum when varying the chemical potential at moderate interactions, which signals the emergence of Cooper pairing. In contrast, the particle conductance is unexpectedly enhanced even before the gas is expected to turn into a superfluid, continuously rising from the plateau at [Formula: see text] for weak interactions to plateau-like features at nonuniversal values as high as [Formula: see text] for intermediate interactions. For strong interactions, the particle conductance plateaus disappear and the spin conductance gets suppressed, confirming the spin-insulating character of a superfluid. Our observations document the breakdown of universal conductance quantization as many-body correlations appear. The observed anomalous quantization challenges a Fermi liquid description of the normal phase, shedding new light on the nature of the strongly attractive Fermi gas.

A thermoelectric heat engine with ultracold atoms.

Thermoelectric effects, such as the generation of a particle current by a temperature gradient, have their origin in a reversible coupling between heat and particle flows. These effects are fundamental probes for materials and have applications to cooling and power generation. Here, we demonstrate thermoelectricity in a fermionic cold atoms channel in the ballistic and diffusive regimes, connected to two reservoirs. We show that the magnitude of the effect and the efficiency of energy conversion can be optimized by controlling the geometry or disorder strength. Our observations are in quantitative agreement with a theoretical model based on the Landauer-Büttiker formalism. Our device provides a controllable model system to explore mechanisms of energy conversion and realizes a cold atom-based heat engine.

A descriptive analysis of personality and gender at the Louisiana State University School of Veterinary Medicine.

The goals of this study were to explore the Myers-Briggs Type Indicator profile and gender differences of Louisiana State University veterinary students. A 12-year composite sample (N = 935) revealed that the personality profile was different from the published US population norm, but similar to the bimodal ESTJ-ISTJ profile found in Louisiana medical students. Significant gender differences were found among six of the 16 types. A 12-year trend analysis revealed a significant shift away from the prototypical ESTJ-ISTJ profile, culminating in a discernable heterogeneous profile for both males and females in the last four years. Composite scores for the 2004-2007 cohort (N = 331) revealed that the predominant types for women were ENFP, ESFJ, ESTJ, ISFJ, and ISTJ. For men, the predominant types were ESTJ, ESTP, INTP, and ISTJ. Post hoc tests confirmed significant gender differences for ESTP, INTP, ISTP, and ESFJ types. The evidence of significant gender differences and confirmation that personality profiles have begun to vary widely across the Myers-Briggs Type Indicator spectrum in the last four years have implications at the practical and theoretical levels. This could have profound effects on pedagogical considerations for faculty involved in veterinary medical education.